JP2016222474A - Separation method of laminated glass and separation method of glass in solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retrieve one of glass plates kept in a single plate form when separating laminated glass by using a stripping solution.SOLUTION: Provided is a separation method of laminated glass configured by bonding first glass exhibiting a first impact strength and second glass exhibiting a second impact strength that is stronger than the first impact strength via an adhesive layer, which includes: a step of forming a crack in the first glass by applying an external force that is stronger than the first impact strength and weaker than the second impact strength to laminated glass; a step of making the stripping solution come in contact with the adhesive layer via the crack; and a step of separating the first glass and the second glass from each other.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for separating laminated glass and a method for separating glass in a solar cell module.

  In recent years, with regard to solar cells, efforts have been reported to collect and recycle those that have reached the end of their life after being sold and used in the market or those that have been judged defective in the manufacturing process. For example, when recycling used solar cell modules, first remove the frame (for example, aluminum metal protective frame) or terminal box from the solar cell module, then remove the frame, etc. It isolate | separates into a battery element board | substrate, a surface protection material (cover glass), and a back surface protection material (back sheet | seat).

  The solar cell element substrate is disposed between the front surface protective material and the back surface protective material, and each member is sealed and bonded with a sealing material (for example, a resin such as EVA), so that these members are separated from each other. Therefore, it is necessary to remove the sealing material. Conventionally, as a method for removing a sealing material in recycling of solar cells, a method of burning a sealing material by putting the module into a heat treatment furnace (see, for example, Patent Document 1) is known. Has the disadvantage of consuming a great deal of energy to operate the furnace. Therefore, there is a need for a solar cell recycling method that consumes less energy.

  Here, when the solar cell element substrate is configured using a glass substrate, the glass substrate and the cover glass form a laminated glass structure. As a method of separating the laminated glass into individual glasses, a method of forming a crack in the laminated glass and reducing the adhesive strength of the intermediate film by causing the intermediate film of the laminated glass to contain a release liquid from the crack (see Patent Document 2). It has been known.

JP 2014-108375 A Japanese Unexamined Patent Publication No. 7-17747

  However, in Patent Document 2, since the laminated glass is composed of two glass plates made of the same material, both glass plates are cracked by an external force exceeding a certain strength, and both glass plates are fragmented. End up. Therefore, it is impossible to recover the glass in a single plate state without cracks.

  This invention is made | formed in view of said point, and one of the objectives is to collect | recover one glass with the state of a single plate in the separation method of the laminated glass using a peeling liquid. .

  In order to solve the above-described problem, according to one embodiment of the present invention, a first glass having a first impact strength and a second glass having a second impact strength larger than the first impact strength are bonded by an adhesive layer. A method for separating laminated glass configured as described above, wherein a crack is formed in the first glass by applying an external force having a strength larger than the first impact strength and smaller than the second impact strength to the laminated glass. A method for separating laminated glass, comprising: a step of bringing a release liquid into contact with the adhesive layer through the crack; and a step of separating the first glass and the second glass from each other.

  According to another aspect of the present invention, in the above aspect, in the step of forming a crack in the first glass, the laminated glass is bent by applying a load to the laminated glass from the second glass side. A method for separating laminated glass, including a step of applying the external force to the laminated glass from the side of the first glass.

  Another embodiment of the present invention is the laminated glass separation method according to the above-described embodiment, wherein the step of forming a crack in the first glass is a step of forming a crack that reaches the adhesive layer. .

  According to another aspect of the present invention, in the above aspect, in the step of bringing the release liquid into contact with the adhesive layer through the crack, the laminated glass in which a crack is formed in the first glass is used as the release liquid. This is a method for separating laminated glass, which is a step of immersing in.

  Another aspect of the present invention is a laminated glass according to the above aspect, further including a step of removing the adhesive layer remaining on the surface of the separated first glass or the second glass by polishing. This is a separation method.

  Another embodiment of the present invention is a solar cell element configured using a glass substrate, a cover glass that protects the solar cell element, and a seal filled between the solar cell element and the cover glass. A glass separation method in a solar cell module comprising a stopper, wherein an external force having a strength larger than the impact strength of the glass substrate and smaller than the impact strength of the cover glass is applied to the solar cell module. Separation of glass in a solar cell module, comprising: a step of forming a crack; a step of bringing a release liquid into contact with the sealing material through the crack; and a step of separating the solar cell element and the cover glass from each other. Is the method.

  According to the present invention, in the method for separating laminated glass using a stripping solution, one glass can be recovered as a single plate.

1 is a cross-sectional configuration diagram of a solar cell element substrate 10 and a solar cell module 1. FIG. FIG. 5 is a process diagram showing each process of the method for recycling the solar cell module 1. It is a figure showing the solar cell module in the intermediate stage of recycling.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example the case where the present invention is applied to recycling of solar cells.

  First, with reference to FIG. 1, the structure of the thin film solar cell module which is a recycling object is demonstrated. FIG. 1A is a cross-sectional configuration diagram of a solar cell element substrate formed by laminating a back electrode layer, a light absorption layer, and a transparent conductive film on a substrate, and FIG. 1B shows the solar cell. It is a cross-sectional block diagram of the solar cell module comprised by adhere | attaching the surface protection material and the back surface protection material on the element substrate with the sealing material.

  As shown in FIG. 1A, the solar cell element substrate 10 is configured by laminating a back electrode layer 102, a light absorption layer 103, and a transparent conductive film 104 in this order on a glass substrate 101. A thin film solar cell in which the back electrode layer 102 / light absorption layer 103 / transparent conductive film 104 are laminated in order from the glass substrate 101 side is called a substrate type thin film solar cell, and the transparent conductive film 104 side serves as a light receiving surface of the solar cell. . The present invention is not limited to substrate-type thin film solar cells, and is a superstrate in which a transparent conductive film / light absorption layer / back electrode layer is laminated in order from the glass substrate side, and the substrate side serves as a light receiving surface. The present invention can be similarly applied to a type thin film solar cell.

  The glass substrate 101 has a first impact strength. In this specification, the impact strength of glass is an index representing the strength of glass against impact, and is the limit (maximum) that can maintain the original shape of the glass without causing cracks when an external force (impact) is applied to the glass. Of external force). That is, when an external force smaller than the impact strength is applied to a certain glass, cracks do not occur, but when an external force greater than the impact strength is applied, a crack is generated in the glass and the glass is destroyed. Therefore, when the glass substrate 101 receives an external force larger than the first impact strength, the glass substrate 101 is cracked and divided into a plurality of small plate pieces. In addition, since the impact strength of glass greatly depends on the compressive strength which is one index of mechanical properties of glass, the compressive strength can be used as an index indicating the impact strength.

  The back electrode layer 102 is made of, for example, a transition metal such as Mo (molybdenum). The light absorption layer 103 is made of, for example, a compound semiconductor (CIS, CIGS, CZTS, etc.), thin film silicon, an organic semiconductor, or the like. The transparent conductive film 104 is, for example, zinc oxide (ZnO), indium tin oxide (ITO), or the like.

  FIG. 1B shows a cross-sectional configuration of the solar cell module 1 in which the solar cell element substrate 10 shown in FIG. As shown in FIG. 1 (B), the solar cell module 1 includes a solar cell element substrate 10 disposed between a surface protective material 11 and a back surface protective material 12, and between the surface protective material 11 and the solar cell element substrate 10. The back surface protection material 12 and the solar cell element substrate 10 are sealed with sealing materials 13A and 13B, respectively.

  The surface protective material 11 is a cover glass made of, for example, tempered glass, and functions to protect the light receiving surface of the solar cell. The back surface protective material 12 is a member for preventing moisture from entering the inside of the solar cell module 1. As an example, a back sheet formed by laminating PET (polyethylene terephthalate) and aluminum foil is applied. The sealing materials 13 </ b> A and 13 </ b> B cover and seal the periphery of the solar cell element substrate 10, and function as an adhesive layer that bonds the solar cell device substrate 10, the surface protection material 11, and the back surface protection material 12. Specific examples of the sealing materials 13A and 13B are EVA (ethylene vinyl acetate), PVB (polyvinyl butyral), and the like. Further, around the end of the solar cell module 1, for example, an aluminum metal frame 14 is bonded with an adhesive such as butyl rubber, and the end of the solar cell module 1 is protected by the frame 14.

  Here, the cover glass (surface protective material) 11 has a second impact strength larger than the first impact strength. That is, when the cover glass 11 receives an external force greater than the second impact strength, it cracks and is divided into a plurality of small plate pieces. However, if the applied external force is smaller than the second impact strength, the cover glass 11 does not crack. It remains intact. Therefore, when an external force having a strength larger than the first impact strength and smaller than the second impact strength is applied to the solar cell module 1, only the glass substrate 101 (solar cell element substrate 10) cracks, and the cover glass No cracks will occur in 11.

  Next, with reference to FIG. 2, the recycling method of the thin film solar cell module mentioned above is demonstrated. FIG. 2 is a process diagram showing each process of the thin-film solar cell module recycling method according to the embodiment.

  First, in step S1, the frame 14 is removed from the solar cell module 1. When removing the frame 14 from the solar cell module 1, for example, after removing the screws used to connect the sides of the rectangular frame 14, the outer side of the rectangle (FIG. 1 ( It is preferable to take a method in which a load is mechanically applied toward the left direction in B). At this time, the adhesive that bonds the frame 14 to the solar cell module 1 may be softened by locally applying heat to the frame 14. When members (for example, a terminal box) other than the frame 14 are attached to the solar cell module 1, these members are also removed from the solar cell module 1 in step S1.

  Next, in step S2, the back surface protective material 12 and the sealing material 13B on the back surface protective material 12 side are removed from the solar cell module 1 from which the frame 14 has been removed. For example, the back surface protective material 12 and the sealing material 13B can be mechanically removed using a tool or apparatus for cutting or grinding. Through this step, the solar cell module 1 is a thin film layer including a back electrode layer 102, a light absorption layer 103, and a transparent conductive film 104 between a glass substrate 101 and a cover glass 11, as shown in FIG. And the shape of the laminated glass 2 by the two glass plates of the structure where 13 A of sealing materials by the side of the cover glass 11 was inserted | pinched.

  Next, in step S <b> 3, an external force is applied to the laminated glass 2 obtained as described above to form a crack in the glass substrate 101 that is one glass constituting the laminated glass 2. The magnitude of the external force applied to the laminated glass 2 is greater than the first impact strength and less than the second impact strength. Therefore, cracks are formed only in the glass substrate 101 (solar cell element substrate 10) in this step, and no cracks are formed in the cover glass 11 which is the other glass constituting the laminated glass 2.

  As a specific method of step S3, as shown in FIG. 3 (B), a load is applied to the laminated glass 2 from the cover glass 11 side to bend the laminated glass 2, and the glass substrate is in that state. It is preferable to apply an external force (impact) to the laminated glass 2 from the 101 side. In order to apply a load to the laminated glass 2, for example, a method of fixing the end portion (four sides or four corners) of the laminated glass 2 so as not to move and pressing the vicinity of the central portion of the cover glass 11 with a pad or the like that is movable by air pressure. Can be taken. As a method for applying an external force to the glass substrate 101, for example, a method of hitting the glass substrate 101 with an impact tool such as a hammer, a method of applying an ultrasonic wave by applying an ultrasonic transducer to the surface of the glass substrate 101, a predetermined steel ball A method of dropping onto a glass substrate 101 from a height, a method of applying a pendulum type shot bag to the glass substrate 101 as in the shot bag test prescribed in JIS R 3205, and a stamping portion of an auto punch on the glass substrate 101 A hitting method or the like can be applied.

  In this way, a crack C as shown in FIG. 3C is formed in the glass substrate 101 by step S3. Here, thin film layers (the back electrode layer 102, the light absorption layer 103, and the transparent conductive film 104) are present on the glass substrate 101, but cracks formed in the glass substrate 101 extend to this thin film layer. . That is, the crack C is formed integrally with the solar cell element substrate 10 and reaches the surface of the sealing material 13A. Therefore, in the crack C portion, the surface of the sealing material 13A is exposed.

  Next, in step S4, the stripping solution is brought into contact with the sealing material 13A through the crack formed in the glass substrate 101. For example, by immersing the laminated glass 2 in which the crack is formed in a stripping solution, the stripping solution can enter the crack C of the glass substrate 101 as shown in FIG. The stripping solution that has entered the crack C penetrates into the inside of the sealing material 13A from that portion and swells the sealing material 13A. By forming a large number of cracks in the glass substrate 101 in step S3, the area where the sealing material 13A comes into contact with the stripping solution is increased, and the stripping solution can quickly penetrate into the entire sealing material 13A. . In order to accelerate the penetration of the stripping solution, it is effective to heat the stripping solution to, for example, 60 to 80 ° C. or to apply ultrasonic vibration to the stripping solution using an ultrasonic oscillator. Instead of immersing the laminated glass 2 in the stripping solution, a method of dropping the stripping solution on the crack portion of the glass substrate 101 or a method of spraying / spreading may be used.

  A stripping solution having an action of swelling the sealing material 13A can be appropriately selected and used depending on the type of the sealing material 13A. For example, an organic solvent or a mixture of a surfactant and water can be used as the stripping solution. Moreover, you may use the peeling liquid which did not swell sealing material 13A but had the effect | action which makes it melt | dissolve. When the sealing material 13A swells or dissolves in this way, the adhesive force between the cover glass 11 and the glass substrate 101 decreases or disappears, and the cover glass 11 and the glass substrate 101 can be separated.

  Next, in step S5, the cover glass 11 and the glass substrate 101 are separated from each other. Since the adhesive strength of the sealing material 13A is reduced or eliminated in step S4, the cover glass 11 and the glass substrate 101 can be easily separated. Since the cover glass 11 is not cracked, it is possible to collect the cover glass 11 in the form of a complete single plate. On the other hand, since the glass substrate 101 is cracked, the glass substrate 101 is recovered in a form fragmented into small pieces.

  Next, in step S <b> 6, the residue of the sealing material 13 </ b> A and the thin film layer are removed from the glass substrate 101. Specifically, after the residue of the swollen sealing material 13A adhering to each small piece of the glass substrate 101 is dried, the residue of the sealing material 13A and the thin film layer are polished by polishing the surface of each small piece. Remove. In order to polish the small pieces of the glass substrate 101, for example, a plurality of small pieces can be simultaneously put into one drum and stirred, and polishing can be performed by rubbing the small pieces together. The small piece of the polished glass substrate 101 can be reused as a raw material such as glass fiber. Further, the glass powder generated by polishing and the metal powder derived from the thin film layer can be separated and collected for each material and reused.

  Even when the residue of the sealing material 13A adheres to the cover glass 11 separated in step S5, it is desirable to polish the surface of the cover glass 11 to remove the residue of the sealing material 13A. Since the cover glass 11 thus collected and polished is in the form of a single plate, it can be reused as it is or as a cover glass for a solar cell module after cutting and shaping into a desired shape as necessary. It is.

  As described above, in the present embodiment, a crack is formed in the glass substrate 101, and the peeling solution is brought into contact with the sealing material 13A through the crack. Thereby, the stripping solution can be quickly infiltrated into the entire sealing material 13A, and the cover glass 11 and the glass substrate 101 can be efficiently separated. Furthermore, since the cover glass 11 does not crack, the cover glass 11 can be effectively reused in the form of a single plate.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various change is possible within the range which does not deviate from the summary. For example, the application target of the present invention is not limited to solar cells, and the present invention can be equally applied as long as it has a laminated glass structure made of two glasses having different impact strengths. It is.

  The present invention can be applied to a laminated glass structure composed of two glasses having different impact strengths. However, the present invention is applied to a thin film solar cell module in which a thin film solar cell element is formed on one glass plate. Are particularly useful. Because various metals are used for the solar cell element, when the thin film solar cell module is disassembled, the glass cell fragments on which the solar cell element is formed and the solar cell element are formed. This is because it is desirable in terms of recycling that it is desirable to prevent coexistence with broken glass plate pieces, in other words, to separate glass pieces with solar cell elements and glass pieces made of single glass. Therefore, when the present invention is applied, one glass plate on which the solar cell element is not formed (that is, the cover glass) can be taken out as a single glass plate, and thus the solar cell element is formed. It is easy to separate the glass plate fragments from a single glass plate on which no solar cell element is formed, which is extremely useful.

DESCRIPTION OF SYMBOLS 1 Solar cell module 2 Laminated glass 10 Solar cell element substrate 11 Surface protection material (cover glass)
12 Back surface protective material 13A Sealing material 13B Sealing material 14 Frame 101 Glass substrate 102 Back surface electrode layer 103 Light absorption layer 104 Transparent conductive film C Crack

Claims (6)

A method for separating a laminated glass, wherein a first glass having a first impact strength and a second glass having a second impact strength larger than the first impact strength are bonded by an adhesive layer,
Forming a crack in the first glass by applying an external force greater than the first impact strength and less than the second impact strength to the laminated glass;
A step of bringing a peeling solution into contact with the adhesive layer through the crack;
Separating the first glass and the second glass from each other;
Method for separating laminated glass including   The step of forming a crack in the first glass includes the step of applying the external force from the first glass side in a state where the laminated glass is bent by applying a load to the laminated glass from the second glass side. The method for separating laminated glass according to claim 1, comprising a step of adding to the laminated glass.   The method for separating laminated glass according to claim 1 or 2, wherein the step of forming a crack in the first glass is a step of forming a crack that reaches the adhesive layer.   The step of bringing the peeling solution into contact with the adhesive layer through the crack is a step of immersing the laminated glass in which the crack is formed in the first glass in the peeling solution. The method for separating laminated glass according to Item 1.   The method for separating laminated glass according to any one of claims 1 to 4, further comprising a step of removing the adhesive layer remaining on the surface of the separated first glass or second glass by polishing. . A solar cell module comprising: a solar cell element configured using a glass substrate; a cover glass protecting the solar cell element; and a sealing material filled between the solar cell element and the cover glass. A separation method,
Forming a crack in the glass substrate by applying to the solar cell module an external force having a strength larger than the impact strength of the glass substrate and smaller than the impact strength of the cover glass;
A step of bringing a peeling solution into contact with the sealing material through the crack;
Separating the solar cell element and the cover glass from each other;
A method for separating glass in a solar cell module.